Extending STR markers in Y chromosome haplotypes.

Area of Science:

• Forensic Genetics
• Population Genetics
• Human Molecular Genetics

Background:

• Y-chromosome Short Tandem Repeats (Y-STRs) are crucial for male lineage tracing and forensic identification.
• Previous population studies on Y-STRs have limitations in discriminatory power.
• Expanding the number of Y-STR loci enhances haplotype resolution.

Purpose of the Study:

• To develop and validate multiplex reactions for 16 Y-STR loci.
• To extend population genetic data for specific Y-STR loci (GATA A7.1, GATA A7.2, GATA C4, GATA H4) in a northern Portuguese sample.
• To assess the forensic utility of an expanded Y-STR marker set.

Main Methods:

• Development of two multiplex polymerase chain reactions (PCR) for amplifying 16 Y-STRs.
• Analysis of 208 male individuals from northern Portugal.
• Haplotype diversity calculations and sequence analysis of novel alleles.

Main Results:

• 199 distinct haplotypes were identified using the 16 Y-STR markers.
• Overall haplotype diversity was high (0.9996), with 190 unique haplotypes.
• The expanded Y-STR set, particularly the 8 novel markers, demonstrated higher haplotype diversity compared to the core set.

Conclusions:

• The developed multiplex Y-STR systems are effective for forensic applications.
• Inclusion of additional Y-STR markers significantly increases haplotype diversity, aiding in individual identification.
• Sequence data for new alleles of GATA C4 and GATA H4 provide valuable information for forensic interpretation.